Simple AC Power distribution box

Started by Rackbuilder, November 26, 2011, 01:15:07 PM

Previous topic - Next topic

Rackbuilder

Building a power supply for my rack project in a 2U case. I have the power supply design all ready but I just want to make sure I"m not missing anything here. I will be using Neutrik PowerCon connectors for all my rack units as drilling the enclosures is much easier than with an IEC input, and they look cool and take up less space!

Forgive my simple little diagram, but I just wanted to see if I was missing anything here. Inline fuse on the live side, heavy duty dpdt switch for both the live and neutral like in an amp. Everything else simply strung together.

Just FYI - the mains will go through a professional Furman unit before hitting this box.





I am wondering if there is any advantage to a star grounding and parallel wiring technique as opposed to simply stringing them together?

Thanks!

R.G.

This set off all kinds of red flags in my head when I read it, so I went and looked it up. Sure enough, the notes on it say that it's rated at 20A/250V, and that it carries safety ground, built-in sequencing of connections, and is UL/etc. rated.

However, the description then goes on to say:
QuoteNote: PowerCon® is not designed to be a "mains" connector or for speaker/amplifier applications.

It strikes me as very odd that it should wrap itself in seemingly-good-enough specs for mains connection, then flatly say not to do that. In any case, to me that's a moot issue.

My opinion on this issue is that no amount of ease of drilling/cutting is worth having connectors which carry mains power not look like mains power. It seems a lot like keeping a pet rattlesnake inside your equipment - it sets a mental trap for you if you're ever tired or careless some day long in the future; worse, it sets the same trap for people who *didn't* decide to set this up.

Being safe with AC mains power is a mental discipline as much as a physical one.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Rackbuilder

Thanks R.G. but I am confused....why can this not replace a standard IEC cable? I have seem them in lots of other custom audio equipment. I obviously don't want to do something that is not safe. the equipment it would be connected to would be drawing less than 2amps each, max. Mostly just other racks containing analog effects pedals, other rack gear, etc.

From the Website..

The powerCON is a lockable equipment AC connector. It's used in the audio business for the power lines of lighting applications, amplifiers, etc. It can be used as power supply for industrial applications with the advantage of it's locking system in comparison to standard non locking MAINS* connector. The connectors fulfill all current safety standards such as SEV, UL, CSA and VDE and uses a colored power inlet-outlet coding to prevent a short circuit. To transmit 20A @ 250V it has a thicker silver plating (20µ) and an enlarged isolation between the Faston contacts. * Not to be used in the wall of a building structure as a mains power connector.

http://www.canford.co.uk/Products/22602/42-9477_CANFORD-MDU7SQ-AC-MAINS-POWER-DISTRIBUTION-UNIT-Switch-sequence-red-grey

R.G.

#3
Quote from: Rackbuilder on November 26, 2011, 02:42:53 PM
Thanks R.G. but I am confused....why can this not replace a standard IEC cable? I have seem them in lots of other custom audio equipment. I obviously don't want to do something that is not safe. the equipment it would be connected to would be drawing less than 2amps each, max. Mostly just other racks containing analog effects pedals, other rack gear, etc.
It clearly can. I'm just overly cautious when AC mains power is involved. And from what you found:
Quote
From the Website..
* Not to be used in the wall of a building structure as a mains power connector.
That answers my question about why they'd specify it like a mains power connector, then warn you not to use it as one.

That just gets me back to my issue with a mains outlet that doesn't look like a mains outlet. That still scares me; not for myself, as (if I had built the box with it in there) I would know to keep fingers, toes, keys, forks, and so on out of it, and I would read the clearly lettered warning label beside this that tells people it's mains power, but it scares me for other (nominally) adult people who have been conditioned to think they know what a mains outlet looks like and treat it with respect.

But that is not a factual issue, clearly, as the connector is specified and approved for such use. If it's common in the industry, then use your own judgement.

I now return you to your regularly scheduled project.  :icon_biggrin:

Quote
Forgive my simple little diagram, but I just wanted to see if I was missing anything here. Inline fuse on the live side, heavy duty dpdt switch for both the live and neutral like in an amp. Everything else simply strung together.
Nope. Fuse the hot side, break both lines with a DPDT switch. That's fine.

QuoteI am wondering if there is any advantage to a star grounding and parallel wiring technique as opposed to simply stringing them together?
Probably not. This is how a power strip and in fact the outlets in the walls are wired.

R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

nexekho

Perhaps I'm missing something, but isn't this reinventing the wheel that is the power strip?
I made the transistor angry.

Rackbuilder

I think I misunderstood the importance of what you were saying earlier...that to the unaware, this does not flash "DANGER" like a typical IEC or wall plug does. I completely understand what you are saying and will take be sure to take precaution.

I appreciate your input Mr. Keen! (Long time lurker here on the board)

Nexekho,

Yes, to a certain extent. But I am building several custom rack units with different effects, etc in them, and have had a lot of trouble with drilling/cutting for IEC connectors. These nice D style plugs are simple to cut and mount, just like an XLR plug, making my life much easier!

The power unit will feed some DC pedals as well as some of the other custom rack gear with these PowerCon units on them.

Thanks!

PRR

#6
> it's rated at 20A/250V
> Note: PowerCon is not designed to be a "mains" connector


At first I was confused with SpeakOn, the speaker connector.

There seems to be conflicting information on PowerCon. I think they are drawing a fine line with "mains". It clearly is a power connector but for "downstream" uses such as we would do lampcord, not upstream of wall-outlet or other High Available Surge point.

BTW, XLR is rated 250V 10 Amps (in 3-pin). It was a common speaker connector on large rigs. There is confusion with XLR mikes, so Bad Idea. Then big rigs started pulling well over 10 Amperes at the amplifier outputs, over-cooked XLRs fail, and this

I am reminded of the very early photo-flash. We did not have a vast array of cord/plug types. Many had a plain lamp outlet/plug and we remoted the flash from the camera with plain lamp extension cord. Later we had power-packs for strobe-flash units. So in a busy photo shoot there's all these identical cords but if you get them wrong you waste a flash-bulb or discharge a power pack or ruin the contacts in a costly shutter.

You can get US-type 3-pin male chassis receptacles which go in a round hole, about 2" diameter. HomeDepot may have them.

Leviton 5278-FWP


Leviton 5278-C


It is generally acceptable to run cable out through a Heyco grip and put a male cord-end on it.
  • SUPPORTER